1. Field of the Invention
The present invention relates to a method of folding an airbag so as to form the airbag in a rolled-up shape and a folding device that is to be used in the method. An airbag is folded and installed in a vehicle and is deployed while unfolding folds by introducing an inflation gas thereinto so as to be inflated and disposed at a predetermined place to thereby protect occupants or pedestrians.
2. Related Art
Conventionally, in a head protecting airbag device, for example, when it is to be installed in a vehicle, the airbag is folded and housed on an upper edge side of windows, and as this occurs, there exists a case where a rolled-up shape in which the airbag is spirally folded is provided in order to be housed (refer, for example, to JP-A-2004-58848).
Then, when the air bag is formed in such a rolled-up shape, there has been used, for example, a folding method which uses two folding rods (refer, for example, to JP-A-7-186865). In this folding method, a part of the airbag is held with the two folding rods, and then, the two folding rods are rotated while they hold the airbag therebetween, so that the airbag is wound around the two folding rods in a spiral manner. Thereafter, the two folding rods are pulled out of the airbag so wound up to leave a rolled-up shape on the airbag.
In the conventional folding method, however, the airbag may slide off between the two folding rods when the folding rods are rotated. Since, in case this actually occurs, the intended roll folding becomes impossible, the folding needs to be carried out while a strong holding force is being applied thereto.
However, in a case where the two folding rods are rotated with such a strong holding force applied thereto so as to produce a spirally wound airbag part therearound to thereby form a rolled-up shape, the two folding rods needs to be separated apart from each other when they are pulled out of the folded airbag. However, the spirally folded airbag itself may becomes a restriction to the required movement by sticking around the rods, and as this actually occurs, it becomes difficult to pull out the two folding rods from the airbag. In particular, when attempting to make a compact rolled-up shape, this type of problem tends to be caused.